JP2022153410A - Release film for ceramic green sheet manufacturing process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a release film for ceramic green sheet manufacturing process, excellent in detachability of a ceramic green sheet.

SOLUTION: There are provided release films 1, 2 for ceramic green sheet manufacturing process, having a substrate 11 and a release agent layer 12 arranged in a single surface side of the substrate 11, in which the release agent layer 12 is formed from a release agent composition containing an active energy ray curable compound having no polyorganosiloxane chain nor silsesquioxane skeleton (A), an active energy ray curable compound having polyorganosiloxane chain and no silsesquioxane skeleton (B), a compound having a silsesquioxane skeleton (C), and a photoinitiator (D).

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to a release film used in the process of manufacturing ceramic green sheets.

2. Description of the Related Art Conventionally, in order to manufacture laminated ceramic products such as laminated ceramic capacitors and multilayer ceramic substrates, ceramic green sheets are formed, and a plurality of the obtained ceramic green sheets are laminated and fired.

A ceramic green sheet is formed to have a uniform thickness by coating a release film with a ceramic slurry containing a ceramic material such as barium titanate or titanium oxide. As the release film, a release agent layer formed by subjecting a film substrate to release treatment with a silicone compound such as polysiloxane is usually used.

In recent years, along with the miniaturization and high performance of electronic devices, multilayer ceramic capacitors and multilayer ceramic substrates have been miniaturized and multi-layered, and the thickness of ceramic green sheets has been reduced. When the ceramic green sheet becomes thin and has a thickness of, for example, 3 μm or less after drying, when the ceramic slurry is applied and dried, the surface state of the release agent layer in the release film causes the ceramic green sheet to become thin. Defects such as pinholes and thickness unevenness are likely to occur. In addition, when the molded ceramic green sheet is peeled off from the release film, problems such as breakage due to reduction in the strength of the ceramic green sheet tend to occur.

Therefore, the release film is required to have releasability such that the thin ceramic green sheet formed on the release film can be separated from the release film without breaking or the like.

From the viewpoint of achieving such peelability, Patent Document 1 discloses a release agent layer-forming material containing an active energy ray-curable compound (a1) and a polyorganosiloxane (b1) on one surface of a substrate. and a back coat layer formed using a back coat layer-forming material containing the active energy ray-curable compound (a2) on the other surface of the substrate. A film is disclosed.

Patent No. 5451951

By the way, with the progress of miniaturization and high performance of electronic devices, it is becoming more and more common to form ceramic green sheets having a thickness of less than 1 μm on a release film. Such an extremely thin ceramic green sheet has a very low strength, so when using a conventional release film, it is difficult to separate it from the release film while suppressing problems such as breakage.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a release film for a process of manufacturing a ceramic green sheet, which exhibits excellent release properties of the ceramic green sheet.

In order to achieve the above objects, firstly, the present invention provides a release film for a ceramic green sheet manufacturing process, comprising a base material and a release agent layer provided on one side of the base material, the release film comprising: The active energy ray-curable compound (A) having no polyorganosiloxane chain and silsesquioxane skeleton, and the active energy ray-curable compound having a polyorganosiloxane chain and no silsesquioxane skeleton. (B), a compound (C) having a silsesquioxane skeleton, and a photopolymerization initiator (D). (Invention 1).

In the release film for the ceramic green sheet manufacturing process according to the invention (Invention 1), the release agent layer is formed from the release agent composition containing the compound (C) having a silsesquioxane skeleton, The release agent layer has a relatively high storage elastic modulus, thereby exhibiting excellent release properties from the ceramic green sheet.

In the above invention (invention 1), the compound (C) having a silsesquioxane skeleton preferably has an active energy ray-curable group (invention 2).

In the above inventions (Inventions 1 and 2), the compound (C) having a silsesquioxane skeleton has a basic structural unit of RSiO _1.5 , and R is at least an active energy ray-curable group and an alkyl group. One type is preferred (Invention 3).

In the above inventions (inventions 1 to 3), the compound (C) having a silsesquioxane skeleton preferably has a polyorganosiloxane chain (invention 4).

In the above invention (invention 4), the polyorganosiloxane chain has a repeating structure of a basic structural unit of R ₂ SiO, and the R in the basic structural unit of R ₂ SiO is an active energy ray-curable group and at least one alkyl group (Invention 5).

In the above inventions (Inventions 2, 3 and 5), the active energy ray-curable group is preferably at least one of (meth)acryloyl groups, alkenyl groups and maleimide groups (Invention 6).

In the above inventions (inventions 1 to 6), the compound (C) having a silsesquioxane skeleton preferably has a weight average molecular weight of 1,000 or more and 30,000 or less (invention 7).

In the above inventions (inventions 1 to 7), the active energy ray-curable compound (A) preferably has three or more (meth)acryloyl groups in one molecule (invention 8).

In the above inventions (inventions 1 to 8), the active energy ray-curable compound (A), the active energy ray-curable compound (B) and the compound having a silsesquioxane skeleton ( The ratio of the content of the active energy ray-curable compound (B) to the total content of C) is preferably 0.003 or more and 0.05 or less (Invention 9).

In the above inventions (Inventions 1 to 9), the surface free energy of the surface of the release agent layer opposite to the substrate is preferably 15 mJ/m ² or more and 35 mJ/m ² or less (Invention 10). .

In the above inventions (Inventions 1 to 10), the thickness of the release agent layer is preferably 0.05 μm or more and 2.0 μm or less (Invention 11).

In the above inventions (inventions 1 to 11), the maximum protrusion height (Rp1) on the surface of the release agent layer opposite to the substrate is preferably 5 nm or more and 100 nm or less (invention 12).

In the above inventions (inventions 1 to 12), the maximum protrusion height (Rp2) on the surface of the substrate opposite to the release agent layer is preferably 30 nm or more and 500 nm or less (invention 13).

In the above inventions (inventions 1 to 13), it is preferable to provide an antistatic layer between the substrate and the release agent layer (invention 14).

The release film for the ceramic green sheet manufacturing process according to the present invention is excellent in releasability of the ceramic green sheet.

1 is a cross-sectional view of a release film for a ceramic green sheet manufacturing process according to a first embodiment of the present invention; FIG. FIG. 4 is a cross-sectional view of a release film for a ceramic green sheet manufacturing process according to a second embodiment of the present invention;

Embodiments of the present invention will be described below.
[Release film for ceramic green sheet manufacturing process]
As shown in FIG. 1 , a release film 1 for a ceramic green sheet manufacturing process according to the first embodiment (hereinafter sometimes simply referred to as “release film 1”) includes a substrate 11 and a second layer of the substrate 11. 1 and a release agent layer 12 laminated on one surface 111 (upper surface in FIG. 1). The substrate 11 has a second surface 112 on the surface opposite to the first surface 111 of the substrate 11 (lower surface in FIG. 1), and the release agent layer 12 is provided on the surface opposite to the substrate 11. A release surface 121 is provided.

Further, as shown in FIG. 2, the release film 2 for the ceramic green sheet manufacturing process according to the second embodiment (hereinafter sometimes simply referred to as "release film 2") includes a base material 11 and a base material 11 antistatic layer 13 laminated on the first surface 111 (upper surface in FIG. 2), and release agent layer 12 laminated on the surface of the antistatic layer 13 opposite to the substrate 11 be. In the release film 2, similarly to the release film 1, the substrate 11 has a second surface 112 on the surface opposite to the first surface 111 of the substrate 11 (lower surface in FIG. 1), and a release agent layer. 12 has a release surface 121 on the side opposite to the antistatic layer 13 .

1. Substrate The substrate 11 of the release films 1 and 2 according to the present embodiment is not particularly limited as long as the release agent layer 12 and the antistatic layer 13 can be laminated thereon. Examples of the substrate 11 include films made of polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polypropylene and polymethylpentene, and plastics such as polycarbonate and polyvinyl acetate, and may be a single layer. However, it may be a multilayer of two or more layers of the same type or different types. Among these, a polyester film is preferable, a polyethylene terephthalate film is particularly preferable, and a biaxially stretched polyethylene terephthalate film is more preferable. Polyethylene terephthalate film is less likely to generate dust during processing, use, etc., so that, for example, it is possible to effectively prevent defects such as ceramic slurry coating failure due to dust and the like. Furthermore, by subjecting the polyethylene terephthalate film to antistatic treatment, the effect of preventing poor coating can be enhanced.

Further, in the substrate 11, for the purpose of improving the adhesiveness with the release agent layer 12 and the antistatic layer 13, if desired, the first surface 111 or both the first surface 111 and the second surface 112 are coated with , a surface treatment such as an oxidation method or a roughening method, or a primer treatment can be applied. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet), flame treatment, hot air treatment, ozone, and ultraviolet irradiation treatment. A thermal spraying method and the like can be mentioned. These surface treatment methods are appropriately selected according to the type of substrate film, but generally corona discharge treatment is preferably used from the viewpoint of effectiveness and operability.

The thickness of the base material 11 is usually 10 μm or more, preferably 15 μm or more, and particularly preferably 20 μm or more. Moreover, the thickness is usually 300 μm or less, preferably 200 μm or less, and particularly preferably 125 μm or less.

The arithmetic mean roughness (Ra0) of the first surface 111 of the substrate 11 is preferably 50 nm or less, particularly preferably 30 nm or less. Also, the arithmetic mean roughness (Ra0) is preferably 2 nm or more, particularly preferably 5 nm or more. The maximum protrusion height (Rp0) on the first surface 111 of the base material 11 is preferably 700 nm or less, particularly preferably 500 nm or less. Also, the maximum protrusion height (Rp0) is preferably 10 nm or more, particularly preferably 30 nm or more. By setting the arithmetic mean roughness (Ra0) or the maximum projection height (Rp0) on the first surface 111 of the base material 11 within the above range, the maximum projection height (Rp0) is set within the above range. This facilitates keeping the arithmetic mean roughness (Ra1) and the maximum projection height (Rp1) of the peeled surface 121 within the ranges described later.

The arithmetic mean roughness (Ra2) of the second surface 112 of the substrate 11 is preferably 50 nm or less, particularly preferably 40 nm or less, and further preferably 30 nm or less. Also, the arithmetic mean roughness (Ra2) is preferably 5 nm or more, particularly preferably 10 nm or more, further preferably 15 nm or more. The maximum projection height (Rp2) on the second surface 112 of the substrate 11 is preferably 500 nm or less, particularly preferably 400 nm or less. Also, the maximum projection height (Rp2) is preferably 30 nm or more, particularly preferably 60 nm or more. By setting the arithmetic mean roughness (Ra2) or the maximum projection height (Rp2) on the second surface 112 of the base material 11 within the above range, the maximum projection height (Rp2) is set within the above range. Therefore, when the release films 1 and 2 on which the ceramic green sheets are formed are wound and stored, the surface shape of the second surface 112 of the substrate 11 is transferred to the ceramic green sheets, thereby forming the ceramic green sheets. It is possible to prevent or suppress the occurrence of defects such as partial thinning. Further, by setting the arithmetic average roughness (Ra2) and the maximum projection height (Rp2) on the second surface 112 of the base material 11 within the above ranges, it is possible to suppress the occurrence of winding misalignment and blocking.

2. Release Agent Layer The release agent layer 12 in the release films 1 and 2 according to the present embodiment is an active energy ray-curable compound (A) having no polyorganosiloxane chain and silsesquioxane skeleton (hereinafter simply “active Sometimes referred to as "energy ray-curable compound (A)") and an active energy ray-curable compound (B) having a polyorganosiloxane chain and having no silsesquioxane skeleton (hereinafter simply referred to as "active energy A release agent composition (hereinafter referred to as “release agent composition It may be called "thing R".). The release agent layer 12 is formed by curing the release agent composition R.

(1) Active energy ray-curable compound (A) having no polyorganosiloxane chain and silsesquioxane skeleton
The active energy ray-curable compound (A) is not particularly limited as long as it does not have a polyorganosiloxane chain and a silsesquioxane skeleton and can be cured by irradiation with an active energy ray. The active energy ray-curable compound (A) is capable of causing a curing reaction between the active energy ray-curable compounds (A) by irradiation with an active energy ray, and the active energy ray-curable compound (B) and the active energy ray-curable compound (B). A curing reaction can occur between them. Furthermore, as described later, when the compound (C) having a silsesquioxane skeleton has an active energy ray-curable group, curing is also performed between the active energy ray-curable compound (A) and the compound (C). reaction can occur. Due to the occurrence of such a curing reaction, a three-dimensional network structure is favorably formed in the release agent layer 12, and the release agent layer 12 has a relatively high storage elastic modulus. As a result, the release films 1 and 2 exhibit excellent release properties with respect to the formed ceramic green sheets. Furthermore, due to the occurrence of the above-described curing reaction, migration of components in the release agent layer 12 from the release agent layer 12 to the ceramic green sheet is also suppressed.

The active energy ray-curable compound (A) is preferably a compound having an active energy ray-curable group. Examples of the active energy ray-curable group include (meth)acryloyl groups, alkenyl groups, maleimide groups, etc. Examples of the alkenyl groups include vinyl groups, allyl groups, propenyl groups, hexenyl groups, and the like. be done. The active energy ray-curable compound (A) preferably has two or more, particularly three or more, of the active energy ray-curable groups in one molecule. When the active energy ray-curable compound (A) has two or more of the active energy ray-curable groups in one molecule, the active energy ray-curable compound (A) has two active energy ray-curable groups of a single type. It may have two or more, or it may have two or more of a plurality of types of active energy ray-curable groups. In the release films 1 and 2 according to the present embodiment, the active energy ray-curable compound (A) easily achieves excellent curability, thereby making it easier for the release films 1 and 2 to achieve excellent peelability. From a viewpoint, it is preferable to have three or more (meth)acryloyl groups in one molecule.

When the active energy ray-curable compound (A) has an active energy ray-curable group, the content of the active energy ray-curable group in the active energy ray-curable compound (A) is the active energy ray-curable compound (A ) is preferably 10 equivalents or more per kg. As a result, when forming the release agent layer 12, even if a relatively thin coating film of the release agent composition R is formed, the coating film exhibits good curability. This makes it easy to form a sufficiently hardened release agent layer 12 .

Specific examples of the active energy ray-curable compound (A) include pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, di Examples include polyfunctional (meth)acrylates such as pentaerythritol penta(meth)acrylate and dipentaerythritol hexa(meth)acrylate. Among these, at least one polyfunctional acrylate of pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate and dipentaerythritol hexa(meth)acrylate is used from the viewpoint of easily achieving excellent curability. It is particularly preferred to use at least one of pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate and dipentaerythritol hexaacrylate.

(2) Active energy ray-curable compound (B) having a polyorganosiloxane chain and no silsesquioxane skeleton
The active energy ray-curable compound (B) is not particularly limited as long as it has a polyorganosiloxane chain, does not have a silsesquioxane skeleton, and can be cured by irradiation with an active energy ray. Since the active energy ray-curable compound (B) has a polyorganosiloxane chain, it can exhibit a function as a release component, thereby enabling the release films 1 and 2 to achieve excellent release properties. Become. In addition, the active energy ray-curable compound (B) can cause a curing reaction between the active energy ray-curable compounds (B) by irradiation with an active energy ray, and as described above, the active energy ray-curable compound A curing reaction can occur between (A). Furthermore, when the compound (C) having a silsesquioxane skeleton as described later has an active energy ray-curable group, the active energy ray-curable compound (B) is also between the compound (C) and A curing reaction can occur. Due to the occurrence of such a curing reaction, a three-dimensional network structure is favorably formed in the release agent layer 12, and the release agent layer 12 has a relatively high storage elastic modulus. This also allows the release films 1 and 2 to exhibit excellent release properties. Furthermore, due to the occurrence of the above-described curing reaction, migration of components in the release agent layer 12 from the release agent layer 12 to the ceramic green sheet is also suppressed. In particular, when the above-described curing reaction occurs in the active energy ray-curable compound (B), it is possible to suppress the migration of the polyorganosiloxane chains to the ceramic green sheets, thereby enabling the production using the ceramic green sheets. It is possible to suppress the deterioration of the performance of the laminated ceramic product.

Preferred examples of the active energy ray-curable compound (B) include polyorganosiloxanes having one or more active energy ray-curable groups in one molecule. Examples of the polyorganosiloxane include polyorganosiloxane having a linear or branched molecular chain.

Examples of the active energy ray-curable group possessed by the polyorganosiloxane include those described above as the active energy ray-curable group possessed by the active energy ray-curable compound (A). The above polyorganosiloxane may have an active energy ray-curable group at either the terminal or the side chain, or may have both the terminal and the side chain. When active energy ray-curable groups are present at the terminals, they may be present at both terminals or may be present at one terminal. In particular, the polyorganosiloxane preferably has an active energy ray-curable group at least one of its terminals from the viewpoint of easiness of uneven distribution on the release surface 121 of the release agent layer 12 .

Moreover, the organic group other than the active energy ray-curable group possessed by the polyorganosiloxane is not particularly limited as long as the release films 1 and 2 according to the present embodiment exhibit excellent peelability. Examples of such organic groups include monovalent hydrocarbon groups having no aliphatic unsaturated bonds. The organic groups may be multiple hydrocarbon groups, which may be the same or different from each other. The hydrocarbon group preferably has 1 to 12 carbon atoms, particularly preferably 1 to 10 carbon atoms. Specific examples of the hydrocarbon group include alkyl groups such as methyl group, ethyl group and propyl group, and aryl groups such as phenyl group and tolyl group, among which methyl group is preferred.

The weight average molecular weight of the active energy ray-curable compound (B) is preferably 400 or more, particularly preferably 1000 or more, further preferably 2000 or more. Moreover, the weight average molecular weight of the active energy ray-curable compound (B) is preferably 20,000 or less, particularly preferably 10,000 or less, further preferably 6,000 or less. When the weight average molecular weight of the active energy ray-curable compound (B) is 400 or more, the effect of improving the peelability can be easily obtained. In addition, when the active energy ray-curable compound (B) has a weight average molecular weight of 20000 or less, it is possible to obtain the effect of suppressing migration to the ceramic green sheet and suppressing defects in the processing process. In addition, the weight average molecular weight in this specification is the value of standard polystyrene conversion measured by the gel permeation chromatography (GPC) method.

Active energy ray curing with respect to the total content of the active energy ray-curable compound (A), the active energy ray-curable compound (B), and the compound (C) having a silsesquioxane skeleton in the release agent composition R The content ratio of the sexual compound (B) is preferably 0.003 or more, particularly preferably 0.005 or more, further preferably 0.007 or more. Also, the ratio is preferably 0.05 or less, particularly preferably 0.03 or less, and further preferably 0.02 or less.

When the ratio of the content of the active energy ray-curable compound (B) is 0.003 or more, the effect of improving the peelability due to the polyorganosiloxane chain of the active energy ray-curable compound (B) is improved. As a result, the release films 1 and 2 can easily exhibit excellent releasability. Further, when the above ratio regarding the content of the active energy ray-curable compound (B) is 0.05 or less, it is possible to sufficiently ensure the content of other components in the release agent composition R. . In particular, the content of the active energy ray-curable compound (A) is sufficiently ensured, and the release agent layer 12 can be sufficiently cured easily. In addition, the content of the compound (C) having a silsesquioxane skeleton is sufficiently ensured, and the effect of improving the peelability due to the compound (C) can be easily obtained.

(3) Compound (C) having a silsesquioxane skeleton
The compound (C) having a silsesquioxane skeleton is not particularly limited as long as it has a silsesquioxane skeleton.

A silsesquioxane skeleton is a siloxane-based skeleton consisting of a basic structural unit of RSiO _1.5 (R is an organic group). This compound (C) having a silsesquioxane skeleton exhibits intermediate properties between inorganic silica consisting of basic structural units of SiO ₂ and polyorganosiloxane consisting of basic structural units of R ₂ SiO. It has both inorganic characteristics such as hardness and heat resistance and organic characteristics such as flexibility and solubility. In particular, since the compound (C) having a silsesquioxane skeleton is a relatively hard component in the release agent composition R, the storage elastic modulus of the release agent layer 12 formed using the release agent composition R is It becomes relatively high, and as a result, the release films 1 and 2 exhibit excellent releasability from the ceramic green sheet.

The silsesquioxane skeleton can generally have various structures, examples of which include a complete cage structure, an incomplete cage structure, a ladder structure, and a random structure. The structure of the silsesquioxane skeleton of the compound (C) having a silsesquioxane skeleton in the present embodiment is not particularly limited, and may be, for example, the structure described above.

R in the basic structural unit (RSiO _1.5 ) of the silsesquioxane skeleton is not particularly limited as long as the release films 1 and 2 exhibit excellent releasability from the ceramic green sheet. Examples include active energy ray-curable groups and alkyl groups (especially methyl groups are preferred), and in particular, at least one of the above Rs is preferably an active energy ray-curable group. Since the compound (C) having a silsesquioxane skeleton has an active energy ray-curable group as R, as described above, the compound (C) having a silsesquioxane skeleton is formed by irradiation with an active energy ray. can perform a curing reaction between the active energy ray-curable compound (A) and the active energy ray-curable compound (B), and also between the compounds (C) having a silsesquioxane skeleton. It can be performed. As a result, the formed release agent layer 12 has a higher storage elastic modulus, making it easier to obtain release films 1 and 2 having excellent release properties.

Examples of the active energy ray-curable group that the compound (C) having a silsesquioxane skeleton has as R include a radical-curable active-energy-ray-curable group and a cationic-curable active-energy-ray-curable group. is mentioned. Examples of the radical-curable active energy ray-curable group include those described above as the active energy ray-curable group possessed by the active energy ray-curable compound (A). Examples of cationic curable active energy ray-curable groups include an oxetanyl group and an epoxy group. Among these, the compound (C) having a silsesquioxane skeleton has a radical curing type of active energy ray-curable group, and more preferably at least one of an acryloyl group and a methacryloyl group.

The compound (C) having a silsesquioxane skeleton in the present embodiment also preferably has a polyorganosiloxane chain. In this case, the compound (C) has a silsesquioxane skeleton consisting of the basic structural unit RSiO _1.5 and a repeating structure of the basic structural unit R ₂ SiO, thereby having a polyorganosiloxane chain. It is preferable that When the compound (C) having a silsesquioxane skeleton has a polyorganosiloxane chain, the compound (C) can function as a release component in the release agent layer 12, so that the release films 1 and 2 obtained are It exhibits better releasability.

The weight average molecular weight of the compound (C) having a silsesquioxane skeleton is preferably 1,000 or more, particularly preferably 3,000 or more, further preferably 5,000 or more. Also, the weight average molecular weight of the compound (C) having a silsesquioxane skeleton is preferably 30,000 or less, particularly preferably 20,000 or less, further preferably 15,000 or less. When the weight-average molecular weight of the compound (C) having a silsesquioxane skeleton is 1000 or more, an effect is obtained that the formed release agent layer 12 can easily obtain a higher storage elastic modulus. Further, when the weight-average molecular weight of the compound (C) having a silsesquioxane skeleton is 30000 or less, an effect of easily obtaining compatibility with the active energy ray-curable compound (A) can be obtained.

In addition, the ratio of the compound (C) having a silsesquioxane skeleton to the total content of the active energy ray-curable compound (A) and the compound (C) having a silsesquioxane skeleton in the release agent composition R The content ratio is preferably 0.03 or more, particularly preferably 0.05 or more, further preferably 0.10 or more. Also, the ratio is preferably 0.50 or less, particularly preferably 0.40 or less, and further preferably 0.30 or less.

When the above-mentioned ratio regarding the content of the compound (C) having a silsesquioxane skeleton is 0.03 or more, the storage elastic modulus of the release agent layer 12 can be effectively improved, resulting in excellent It becomes easy to obtain release films 1 and 2 exhibiting release properties. Further, when the above-mentioned ratio regarding the content of the compound (C) having a silsesquioxane skeleton is 0.50 or less, it is possible to sufficiently ensure the content of other components in the release agent composition R. becomes. In particular, the content of the active energy ray-curable compound (A) is sufficiently ensured, and the release agent layer 12 can be sufficiently cured easily.

(4) Photoinitiator (D)
The photopolymerization initiator (D) contained in the release agent composition R includes an active energy ray-curable compound (A), an active energy ray-curable compound (B), and a compound (C) having a silsesquioxane skeleton. It is preferable to use one suitable for the active energy ray-curable group possessed. In particular, when the compound (C) having a silsesquioxane skeleton has the radical-curable active energy ray-curable group described above, it is preferable to use a photoradical initiator as the photopolymerization initiator (D). . Examples of photoradical initiators include α-aminoalkylphenone-based compounds, α-hydroxyketone-based compounds, aromatic ketones including thioxanthone, and acylphosphine oxides. Among these, α-aminoalkylphenone compounds are preferable from the viewpoint of promoting the polymerization reaction and improving curability.

Examples of α-aminoalkylphenone compounds include 2-methyl-1[4-(methylthio)phenyl]-2-morifolinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4 -morpholinophenyl)-butanone-1,2-dimethylamino-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone and the like, and these Among them, 2-methyl-1[4-(methylthio)phenyl]-2-morifolinopropan-1-one is preferred.

Examples of α-hydroxyketone compounds include 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one , 2-hydroxy-4′-hydroxyethoxy-2-methylpropiophenone, 1-hydroxy-cyclohexyl-phenyl-ketone, oligo{2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl ] Propanone} and the like.

When the compound (C) having a silsesquioxane skeleton has the cationic curable active energy ray-curable group described above, it is preferable to use a photocationic initiator as the photopolymerization initiator (D). Examples of photocationic initiators include sulfonium salt compounds, iodonium salt compounds, phosphonium salt compounds, diazonium salt compounds, ammonium salt compounds, and ferrocene compounds.

The photopolymerization initiator (D) described above can be used alone or in combination of two or more.

The content of the photopolymerization initiator (D) in the release agent composition R is preferably 2 parts by mass or more, particularly 4 parts by mass or more, relative to 100 parts by mass of the active energy ray-curable compound (A). is preferably Moreover, the content of the photopolymerization initiator (D) in the release agent composition R is preferably 15 parts by mass or less, and particularly preferably 12 parts by mass or less. When the content of the photopolymerization initiator (D) is within the range described above, the release films 1 and 2 can easily exhibit excellent release properties.

(5) Other Components In addition to the above components, the release agent composition R according to the present embodiment may optionally contain silica, an antistatic agent, an initiation aid, a dye, a pigment, and other additives. good.

(6) Physical properties of the release film for the ceramic green sheet manufacturing process, etc. The thickness of the release agent layer 12 in the release films 1 and 2 according to the present embodiment is preferably 0.05 μm or more, particularly 0.1 μm or more. It is preferably 0.15 μm or more, more preferably 0.15 μm or more. Also, the thickness is preferably 2.0 μm or less, particularly preferably 1.5 μm or less, further preferably 1.2 μm or less. Since the thickness of the release agent layer 12 is 0.05 μm or more, even if there are projections on the first surface 111 of the base material 11, the concave portions between the projections can be removed by the release agent layer 12. As a result, the release surface 121 has better smoothness, thereby effectively suppressing pinholes and thickness unevenness in the molded ceramic green sheet. In addition, since the thickness of the release agent layer 12 is 2.0 μm or less, curling of the release films 1 and 2 due to cure shrinkage of the release agent layer 12 is effectively suppressed. In addition, the occurrence of blocking when the release film 1 is wound into a roll is effectively suppressed.

In the release films 1 and 2 according to the present embodiment, the arithmetic mean roughness (Ra1) of the release surface 121 of the release agent layer 12 is preferably 10 nm or less, particularly preferably 7 nm or less, and further preferably 5 nm. The following are preferable. Also, the maximum protrusion height (Rp1) of the peeled surface 121 is preferably 100 nm or less, particularly preferably 70 nm or less, and further preferably 50 nm or less.

By setting the arithmetic mean roughness (Ra1) or the maximum projection height (Rp1) of the peeling surface 121 within the above range, particularly by setting the maximum projection height (Rp1) within the above range, peeling can be achieved. The surface 121 can be made sufficiently smooth. For example, even when a thin ceramic green sheet having a thickness of less than 1 μm is formed on the release surface 121, the thin ceramic green sheet has defects such as pinholes and thickness unevenness. is less likely to occur, making it easy to achieve good slurry coatability. Further, by setting the arithmetic mean roughness (Ra1) or the maximum protrusion height (Rp1) of the release surface 121 within the above range, the release property of the ceramic green sheet is further improved, and the thickness is less than 1 μm, for example. Also when the thin-film ceramic green sheets are separated from the release agent layer 12, breakage of the ceramic green sheets is effectively suppressed.

Although the lower limit of the arithmetic mean roughness (Ra1) of the peeling surface 121 is not particularly limited, it is preferably 1 nm or more. Also, the lower limit of the maximum protrusion height (Rp1) of the peeled surface 121 is not particularly limited, but is preferably 5 nm or more.

In the release films 1 and 2 according to the present embodiment, the surface free energy of the release surface 121 of the release agent layer 12 is preferably 15 mJ/m ² or more, and more preferably 18 mJ/m ² or more. is preferably 20 mJ/m ² or more. Moreover, the surface free energy is preferably 35 mJ/m ² or less, particularly preferably 32 mJ/m ² or less, and further preferably 30 mJ/m ² or less. When the surface free energy is within the above range, the occurrence of repelling is effectively suppressed when the ceramic slurry is applied onto the release surfaces 121 of the release films 1 and 2 . In particular, the occurrence of repelling at the peripheral edge portions of the release films 1 and 2 is effectively suppressed, and the problem that the edge portions of the formed ceramic green sheets are thicker than the other portions is also effectively suppressed. be. The method for measuring the surface free energy is as shown in the test examples described later.

3. Antistatic layer The antistatic layer 13 can impart desired antistatic properties to the release film 2 while ensuring the excellent releasability of the release film 2 according to the second embodiment. Not limited. As such an antistatic layer 13, for example, an antistatic layer containing a conductive substance such as a conductive polymer, a cationic antistatic agent, an anionic antistatic agent, a metal fine particle and a nanocarbon material, and a binder resin and a layer comprising a composition for Among these, an antistatic layer composition containing a conductive polymer and a binder resin is preferable because of its excellent antistatic properties.

As the conductive polymer, any of conventionally known conductive polymers can be appropriately selected and used. Among them, polythiophene-based, polyaniline-based, or polypyrrole-based conductive polymers are preferable. Conductive polymers may be used singly or in combination of two or more.

Polythiophene-based conductive polymers include, for example, polythiophene, poly(3-alkylthiophene), poly(3-thiophene-β-ethanesulfonic acid), a mixture of polyalkylenedioxythiophene and polystyrene sulfonate (PSS) ( including doped ones) and the like. Among these, a mixture of polyalkylenedioxythiophene and polystyrene sulfonate is preferred. Examples of the polyalkylenedioxythiophene include poly(3,4-ethylenedioxythiophene) (PEDOT), polypropylenedioxythiophene, poly(ethylene/propylene)dioxythiophene, etc. Among them, poly(3,4- ethylenedioxythiophene) is preferred. That is, among the above, a mixture of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate (PSS-doped PEDOT) is particularly preferred.

Polyaniline-based conductive polymers include, for example, polyaniline, polymethylaniline, and polymethoxyaniline. Polypyrrole-based conductive polymers include, for example, polypyrrole, poly-3-methylpyrrole, and poly-3-octylpyrrole.

The content of the conductive polymer in the antistatic layer composition is preferably 0.1% by mass or more, particularly preferably 0.2% by mass or more, and further preferably 0.3% by mass or more. is preferably Also, the content is preferably 30% by mass or less, particularly preferably 20% by mass or less, and further preferably 10% by mass or less. If the content of the conductive polymer is within the above range, good antistatic performance can be obtained, and the strength of the antistatic layer formed from the antistatic layer composition will be sufficient.

The binder resin used in the antistatic layer composition preferably contains, as a main component, at least one selected from the group consisting of polyester resins, urethane resins and acrylic resins. These resins may be thermosetting compounds or UV-curable compounds.

The antistatic layer composition may contain a cross-linking agent, a leveling agent, an antifouling agent, etc., in addition to the above components.

Any cross-linking agent may be used as long as it can cross-link the above resin. For example, if the resin has a hydroxyl group as a reactive group, it is preferable to use an isocyanate-based cross-linking agent, an epoxy-based cross-linking agent, an amine-based cross-linking agent, a melamine-based cross-linking agent, or the like.

The content of the cross-linking agent is preferably 1 part by mass or more, particularly preferably 5 parts by mass or more, further preferably 10 parts by mass or more, relative to 100 parts by mass of the binder resin. In addition, the content of the cross-linking agent is preferably 50 parts by mass or less, particularly preferably 40 parts by mass or less, and further preferably 30 parts by mass or less with respect to 100 parts by mass of the binder resin. .

Examples of leveling agents that can be used include dimethylsiloxane compounds, fluorine compounds, surfactants, and the like. By containing a leveling agent in the antistatic layer composition, the smoothness of the antistatic layer 13 can be improved, thereby improving the arithmetic mean roughness (Ra1) and the maximum protrusion height (Rp1 ) within the range described above.

The content of the leveling agent in the antistatic layer composition is preferably 0.05% by mass or more, particularly preferably 0.1% by mass or more, and further preferably 0.3% by mass or more. is preferred. The content of the leveling agent in the antistatic layer composition is preferably 10% by mass or less, particularly preferably 5% by mass or less, further preferably 3% by mass or less.

From the viewpoint of antistatic performance, the thickness of the antistatic layer 13 is preferably 10 nm or more, particularly preferably 20 nm or more, further preferably 30 nm or more. From the viewpoint of strength and cost, the thickness is preferably 2000 nm or less, particularly preferably 1500 nm or less, and further preferably 1000 nm or less.

In addition, in the release film 2 according to the second embodiment, the antistatic layer 13 is provided between the base material 11 and the release agent layer 12, but the antistatic layer 13 is not limited to this position, and other positions may be provided in For example, the configuration may be such that the antistatic layer 13 is provided on the second surface 112 side of the base material 11 . Specifically, the release agent layer 12, the substrate 11, and the antistatic layer 13 may be arranged in this order.

4. Manufacturing Method of Release Film for Ceramic Green Sheet Manufacturing Process The release film 1 according to the first embodiment comprises a release film 1 containing a release agent composition R and optionally an organic solvent on the first surface 111 of the substrate 11. The release agent layer 12 can be produced by coating the agent layer forming material, drying it if necessary, and curing it by irradiation with active energy rays to form the release agent layer 12 . As a method for applying the release agent layer-forming material, for example, gravure coating, bar coating, spray coating, spin coating, knife coating, roll coating, die coating, and the like can be used.

As the organic solvent, conventionally known ones can be used as long as they have good solubility for each component of the release agent layer forming material and do not have reactivity. For example, aliphatic hydrocarbons such as hexane, heptane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and ethylene chloride; Alcohols such as methoxy-2-propanol; ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone and cyclohexanone; esters such as ethyl acetate and butyl acetate; cellosolve solvents such as ethyl cellosolve; The amount of the organic solvent used is preferably adjusted so that the solid content concentration is usually in the range of 1 to 60% by mass.

As the active energy rays, ultraviolet rays, electron beams, etc. are usually used, and ultraviolet rays are particularly preferred. The amount of active energy ray irradiation varies depending on the type of energy ray. For example, in the case of ultraviolet rays, the amount of light is preferably 50 to 1000 mJ/cm ² , particularly preferably 100 to 500 mJ/cm ² . In the case of an electron beam, it is preferably about 0.1 to 50 kGy.

By the irradiation of the active energy ray, the active energy ray-curable component (A) in the release agent composition R is polymerized and cured to form the release agent layer 12 .

Also, the release film 2 according to the second embodiment can be manufactured by forming the antistatic layer 13 and the release agent layer 12 on the substrate 11 in this order. The antistatic layer 13 is formed by coating the first surface 111 of the substrate 11 with a coating liquid containing an antistatic layer composition and optionally an organic solvent or water, followed by drying and curing. be able to. The organic solvent and coating method used at this time may be the same as the organic solvent and coating method used to form the release agent layer 12 described above. The release agent layer 12 can be formed on the surface of the formed antistatic layer 13 opposite to the substrate 11 in the same manner as described above.

5. Method of Using Release Films for Manufacturing Process of Ceramic Green Sheets The release films 1 and 2 according to the present embodiment are used for manufacturing ceramic green sheets. Examples of such uses include a method of forming a ceramic green sheet by applying a ceramic slurry to the release surface 121 using a slot die coating method, a doctor blade method, or the like, followed by drying.

A plurality of molded ceramic green sheets are laminated and then fired to form a laminated ceramic product. During this lamination, the release films 1 and 2 are separated from the ceramic green sheets. In the release films 1 and 2 according to the present embodiment, the release agent layer 12 contains a compound (C) having a silsesquioxane skeleton. Since it is formed from the release agent composition, the peeling force at the time of peeling is very small. Therefore, when peeling off the release films 1 and 2 from the ceramic green sheets, it is possible to suppress the occurrence of defects such as breakage of the ceramic green sheets. In particular, the release films 1 and 2 according to the present embodiment can satisfactorily suppress the occurrence of defects such as breakage even when the thickness of the molded ceramic green sheet is very thin, such as less than 1 μm. .

The embodiments described above are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments is meant to include all design changes and equivalents that fall within the technical scope of the present invention.

For example, the second surface 112 of the substrate 11 in the release films 1 and 2, between the substrate 11 and the release agent layer 12 in the release film 1, between the substrate 11 and the antistatic layer 13 in the release film 2, or Another layer may be provided between the antistatic layer 13 and the release agent layer 12 .

EXAMPLES The present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Example 1]
90 parts by mass of pentaerythritol triacrylate (solid content conversion value; the same applies hereinafter) as an active energy ray-curable compound (A) that does not have a polyorganosiloxane chain and a silsesquioxane skeleton, and a polyorganosiloxane chain , 1.0 parts by mass of acrylic-modified polyorganosiloxane (manufactured by Big Chemie, product name “BYK-3500”) as an active energy ray-curable compound (B) having no silsesquioxane skeleton, and silsesquioxane Silsesquioxane having an acryloyl group (manufactured by Toagosei Co., Ltd., product name “AC-SQ TA-100”, indicated as “C1” in Table 1) as the compound (C) having a skeleton, 10 parts by mass, and light 2-methyl-1[4-(methylthio)phenyl]-2-morifolinopropan-1-one (manufactured by BASF, product name “IRUGACURE907”, α-aminoalkylphenone-based Photopolymerization initiator) and 7 parts by mass were diluted with a mixed solvent of isopropyl alcohol and methyl ethyl ketone (mass ratio 3:1) to a solid content concentration of 20 mass % to obtain a material for forming a release agent layer.

The resulting material for forming a release agent layer was applied to a biaxially stretched polyethylene terephthalate (PET) film (thickness: 31 μm, arithmetic mean roughness on the first surface: Ra0: 19 nm, maximum projection height on the first surface). Rp0: 154 nm, second surface arithmetic mean roughness Ra2: 20 nm, second surface maximum protrusion height Rp2: 171 nm). It was applied by a coater and dried at 80° C. for 1 minute. Thereafter, ultraviolet rays were irradiated (accumulated light quantity: 250 mJ/cm ² ) to cure the release agent layer forming material to form a release agent layer, which was used as a release film. The thickness of the release agent layer is the result of measurement by the measurement method described later (the same applies to the following examples, etc.).

[Example 2]
As the compound (C) having a silsesquioxane skeleton, a silsesquioxane having a methacryloyl group (manufactured by Toagosei Co., Ltd., product name “MAC-SQ TA-100”, indicated as “C2” in Table 1) is used. A release film was produced in the same manner as in Example 1, except that

[Example 3]
As the compound (C) having a silsesquioxane skeleton, a silsesquioxane having an acryloyl group and a polyorganosiloxane chain (manufactured by Toagosei Co., Ltd., product name “AC-SQ SI-20”, “C3” in Table 1 A release film was prepared in the same manner as in Example 1, except that the above described) was used.
[Example 4]
As the compound (C) having a silsesquioxane skeleton, silsesquioxane having an acryloyl group and a polyorganosiloxane chain (manufactured by Toagosei Co., Ltd., product name "MAC-SQ SI-20", "C4" in Table 1 A release film was prepared in the same manner as in Example 1, except that the above described) was used.

[Examples 5 and 6]
Except for changing the contents of the active energy ray-curable compound (A) having no polyorganosiloxane chain and silsesquioxane skeleton and the compound (C) having a silsesquioxane skeleton as shown in Table 1, A release film was produced in the same manner as in Example 1.

[Example 7]
Except for changing the contents of the active energy ray-curable compound (A) having no polyorganosiloxane chain and silsesquioxane skeleton and the compound (C) having a silsesquioxane skeleton as shown in Table 1, A release film was produced in the same manner as in Example 3.

[Examples 8 and 9]
A release film was prepared in the same manner as in Example 1, except that the content of the active energy ray-curable compound (B) having a polyorganosiloxane chain and no silsesquioxane skeleton was changed as shown in Table 1. made.

[Example 10]
A release film was produced in the same manner as in Example 1, except that pentaerythritol tetraacrylate was used as the active energy ray-curable compound (A) having no polyorganosiloxane chain and silsesquioxane skeleton.

[Example 11]
A release film was produced in the same manner as in Example 9, except that the thickness of the release agent layer was changed as shown in Table 1.

[Example 12]
A release film was produced in the same manner as in Example 1, except that the thickness of the release agent layer was changed as shown in Table 1.

[Example 13]
As a substrate, a biaxially oriented polyethylene terephthalate (PET) film (thickness 31 μm, arithmetic mean roughness Ra0 on the first surface: 13 nm, maximum protrusion height Rp0 on the first surface: 79 nm, arithmetic on the second surface A release film was produced in the same manner as in Example 1, except that the average roughness Ra2: 14 nm and the maximum projection height Rp2 of the second surface: 85 nm) were used.

[Example 14]
As a substrate, a biaxially oriented polyethylene terephthalate (PET) film (thickness 31 μm, arithmetic mean roughness Ra0 on the first surface: 34 nm, maximum protrusion height Rp0 on the first surface: 516 nm, arithmetic on the second surface A release film was produced in the same manner as in Example 1, except that the average roughness Ra2: 35 nm and the maximum protrusion height Rp2 on the second surface: 530 nm) were used.

[Example 15]
As a substrate, a biaxially oriented polyethylene terephthalate (PET) film (thickness 31 μm, arithmetic mean roughness Ra0 on the first surface: 6 nm, maximum protrusion height Rp0 on the first surface: 27 nm, arithmetic on the second surface A release film was produced in the same manner as in Example 1, except that the average roughness Ra2: 23 nm and the maximum protrusion height Rp2 on the second surface: 188 nm) were used.

[Example 16]
Example except that the thickness of the release agent layer and the content of the active energy ray-curable compound (B) having a polyorganosiloxane chain and not having a silsesquioxane skeleton were changed as shown in Table 1. A release film was prepared in the same manner as in No. 15.

[Comparative Example 1]
A release film was produced in the same manner as in Example 1, except that the compound (C) having a silsesquioxane skeleton was not used.

[Comparative Example 2]
As the active energy ray-curable compound (A) having no polyorganosiloxane chain and silsesquioxane skeleton, pentaerythritol tetraacrylate is used, except that the compound (C) having a silsesquioxane skeleton is not used. , a release film was produced in the same manner as in Example 1.

[Test Example 1] (Measurement of surface free energy of peeled surface)
For the release films obtained in Examples and Comparative Examples, the contact angle of various droplets on the release surface of the release agent layer was measured, and based on the measured value, the surface free energy (mJ/m ² ). The contact angle was measured according to JIS R3257 by the sessile drop method using a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., product name: "DM-701"). For the droplets, diiodomethane was used as the 'dispersion component', 1-bromonaphthalene as the 'dipole component', and distilled water as the 'hydrogen bonding component'. Table 2 shows the results.

[Test Example 2] (Measurement of thickness of release agent layer)
The thickness (μm) of the release agent layer of the release films obtained in Examples and Comparative Examples was measured using a reflective film thickness meter (manufactured by Filmetrics, product name “F20”). Specifically, after cutting the release films obtained in Examples and Comparative Examples into 100 x 100 mm, the release films were placed in a film thickness meter so that the opposite side of the side to be measured was on the suction stage side. , the film thickness was measured at 10 points on the surface of the release agent layer, and the average value was taken as the thickness of the release agent layer. Table 2 shows the results.

[Test Example 3] (Measurement of surface roughness of peeled surface)
A double-sided tape was attached to a glass plate, and the release films obtained in Examples and Comparative Examples were fixed to the glass plate via the double-sided tape so that the surface opposite to the surface to be measured was on the glass plate side. The arithmetic mean roughness (Ra1; nm) and the maximum protrusion height (Rp1; nm) on the release surface of the release film were measured with a surface roughness measuring instrument (manufactured by Mitutoyo, product name "SV-3000S4", stylus type). was used, measurement length: 10 mm, speed: 1.0 mm/sec, filter type: Gaussian, and λc: 0.25 mm. In addition, the measurement was performed 10 times for each of Ra1 and Rp1, and the average value was defined as Ra1 and Rp1 of the release film. Table 2 shows the results.

Table 2 shows the arithmetic mean roughness (Ra0; nm) and maximum projection height (Rp0; nm) on the first surface (surface on the release agent layer side) of the substrate used, and the second surface Arithmetic mean roughness (Ra2; nm) and maximum protrusion height (Rp2; nm) on (the side opposite to the release agent layer) are also shown.

[Test Example 4] (Evaluation of Curability of Release Agent Layer)
For the release films obtained in Examples and Comparative Examples, a waste cloth impregnated with methyl ethyl ketone (manufactured by Ozu Sangyo Co., Ltd., product name “BEMCOT AP-2”) was applied to the surface of the release agent layer with a load of 1 kg/cm ² for 10 reciprocations. polished twice. After that, the release surface was visually observed, and the curability of the release agent layer was evaluated according to the following criteria. In this test (test example 4), the samples evaluated as "C" were not subjected to other tests because satisfactory samples could not be obtained for other tests. Table 2 shows the results.
A: There was no dissolution or falling off of the release agent layer.
B: Partial dissolution of the release agent layer was observed.
C: The release agent layer was completely dissolved and fell off from the substrate.

[Test Example 5] (Evaluation of slurry coatability)
Barium titanate powder (BaTiO ₃ ; manufactured by Sakai Chemical Industry Co., Ltd., product name “BT-03”) 100 parts by mass, polyvinyl butyral resin as a binder (manufactured by Sekisui Chemical Co., Ltd., product name “S-Lec B K BM-2” ), and 4 parts by mass of dioctyl phthalate (manufactured by Kanto Chemical Co., Ltd., dioctyl phthalate deer 1st class) as a plasticizer, and 135 parts by mass of a mixture of toluene and ethanol (mass ratio 6:4), A ceramic slurry was prepared by mixing and dispersing in a ball mill in the presence of zirconia beads and removing the beads.

On the release surface of the release films obtained in Examples and Comparative Examples, the above ceramic slurry was applied with a die coater over a width of 250 mm and a length of 10 m so that the film thickness after drying was 1 μm, and then dried. It was dried in an oven at 80°C for 1 minute. The release film formed with the ceramic green sheets was illuminated with a fluorescent lamp from the release film side, and all surfaces of the formed ceramic green sheets were visually inspected, and the slurry coatability was evaluated according to the following criteria. Table 2 shows the results.
A: There was no pinhole in the ceramic green sheet.
B: 1 to 5 pinholes were generated in the ceramic green sheet.
C: 6 or more pinholes were generated in the ceramic green sheet.

[Test Example 6] (Measurement of peel strength against ceramic green sheet)
A ceramic green sheet was formed on the release surface of the release film by the same procedure as in Test Example 5. The obtained release sheet with the ceramic green sheet was allowed to stand in an atmosphere of 23° C. and 50% RH for 24 hours. Next, an acrylic adhesive tape (manufactured by Nitto Denko Co., Ltd., product name "31B tape") was attached to the surface of the ceramic green sheet opposite to the release sheet, and the ceramic green sheet was cut to a width of 20 mm. This was used as a measurement sample.

The adhesive sheet side of the measurement sample is fixed to a flat plate, and a tensile tester (manufactured by Shimadzu Corporation, product name "AG-IS500N") is used to peel off from the ceramic green sheet at a peel angle of 180 ° and a peel speed of 300 mm / min. The release sheet was peeled off, and the force (peeling force; mN/20 mm) required for peeling was measured. Table 2 shows the results.

[Test Example 7] (Evaluation of defects in ceramic green sheet due to peeled surface)
A ceramic green sheet was formed on the release surface of the release film by the same procedure as in Test Example 5. Next, the release film was peeled off from the ceramic green sheet, and the number of dents on the surface of the ceramic green sheet that was in contact with the peeled surface was counted. Specifically, using an optical interference type surface profile observation device (manufactured by Vecco, product name “WYKO-1100”), observation was performed in PSI mode at 50 magnifications, and the obtained 91.2 × 119.8 μm The number of pits with a depth of 150 nm or more was counted based on the topography image in the range of .

Defect evaluation of the ceramic green sheet due to the release agent layer surface was performed according to the following criteria based on the number of dents. Table 2 shows the results.
A: The number of dents was zero.
B: The number of dents was 1 to 5.
C: The number of dents was 6 or more.
When a capacitor is manufactured from the ceramic green sheet having the dents of the above evaluation C, the resulting capacitor is likely to be short-circuited due to a drop in withstand voltage.

[Test Example 8] (Evaluation of defects in ceramic green sheet by second surface of substrate)
A coating solution obtained by dissolving polyvinyl butyral resin in a toluene/ethanol mixed solvent (mass ratio 6/4) was applied onto a PET film having a thickness of 50 µm so that the thickness after drying was 3 µm, and the temperature was maintained at 60°C. and dried for 1 minute to form a polyvinyl butyral resin layer.

The release films obtained in Examples and Comparative Examples were attached to the polyvinyl butyral resin layer so that the second surface of the substrate of the release film was in contact with the polyvinyl butyral resin layer. After cutting this laminate into a size of 100 mm×100 mm, it was pressed with a load of 5 kg/cm ² to transfer the shape of protrusions on the second surface of the base material of the release film to the polyvinyl butyral resin layer. Next, the release film was peeled off from the polyvinyl butyral resin layer, and depressions with a depth of 500 nm or more were counted on the surface of the polyvinyl butyral resin film that was in contact with the second surface of the release film substrate. Specifically, using an optical interference type surface profile observation device (manufactured by Veeco, product name “WYKO-1100”), PSI mode, 50 magnifications, 91.2 × 119.8 μm range is confirmed The dents to which the shape of the second surface was transferred were counted, and defects of the ceramic green sheet due to the second surface of the substrate were evaluated according to the following criteria. Incidentally, when a capacitor was produced from a green sheet having dents of evaluation C below, short circuits tended to occur due to a decrease in withstand voltage.
A: The number of dents was zero.
B: The number of dents was 1 to 3.
C: The number of dents was 4 or more.

[Test Example 9] (Handling Evaluation)
The release films obtained in Examples and Comparative Examples were evaluated for handleability when rolled. Specifically, the following evaluation criteria were used to evaluate the slipperiness of the release films in contact with each other, the ease with which air could escape when formed into a roll, and the difficulty of causing the release film to be wound out of alignment. Table 2 shows the results.
A: The peeling films in contact with each other had good lubricity, and the release of air was good when the peeling film was formed into a roll.
B: Slightly poor lubricity between the release films in contact with each other, and the release of air when the release film was wound into a roll was slightly poor, and there was no problem although there was a slight deviation in winding.
C . . . The release films in contact with each other had poor lubricity, and when the release film was wound into a roll, the release of air was poor, resulting in significant winding misalignment.

[Test Example 10] (Evaluation of blocking property)
The release films obtained in Examples and Comparative Examples were rolled up into rolls having a width of 400 mm and a length of 5000 m. This release film roll was stored for 30 days in an environment of 40° C. and a humidity of 50% or less. After that, the blocking property was evaluated according to the following criteria when the release film was unwound from the release film roll. Table 2 shows the results.
A: No blocking occurred, and the release film was able to be fed out satisfactorily.
B: Although blocking tended to occur, the release film could be fed out.
C: The release film could not be fed out due to blocking.

As is clear from Table 2, the release films of Examples were excellent in releasability from the ceramic green sheet. In addition, according to the release films of the examples, the ceramic green sheets were less likely to have defects, moreover, blocking was less likely to occur, and the slurry coating properties and handling properties were good.

DESCRIPTION OF SYMBOLS 1, 2... Release film for ceramic green sheet manufacturing processes 11... Base material 111... 1st surface 112... 2nd surface 12... Release agent layer 121... Release surface 13... Antistatic layer

Claims (14)

A release film for a ceramic green sheet manufacturing process comprising a substrate and a release agent layer provided on one side of the substrate,
The release agent layer is
an active energy ray-curable compound (A) having no polyorganosiloxane chain and silsesquioxane skeleton;
an active energy ray-curable compound (B) having a polyorganosiloxane chain and no silsesquioxane skeleton;
a compound (C) having a silsesquioxane skeleton;
A release film for a ceramic green sheet manufacturing process, characterized by being formed from a release agent composition containing a photopolymerization initiator (D). 2. The release film for a ceramic green sheet manufacturing process according to claim 1, wherein the compound (C) having a silsesquioxane skeleton has an active energy ray-curable group. The compound (C) having a silsesquioxane skeleton has a basic structural unit of RSiO _1.5 ,
3. The release film for a ceramic green sheet manufacturing process according to claim 1, wherein said R is at least one of an active energy ray-curable group and an alkyl group. The release film for a ceramic green sheet manufacturing process according to any one of claims 1 to 3, wherein the compound (C) having a silsesquioxane skeleton has a polyorganosiloxane chain. The polyorganosiloxane chain has a repeating structure of basic structural units of R ₂ SiO,
5. The release film for a ceramic green sheet manufacturing process according to claim ₄ , wherein said R in said basic structural unit of said R2SiO is at least one of an active energy ray-curable group and an alkyl group. 6. The release film for a ceramic green sheet manufacturing process according to claim 2, 3 or 5, wherein the active energy ray-curable group is at least one of a (meth)acryloyl group, an alkenyl group and a maleimide group. The release for the ceramic green sheet manufacturing process according to any one of claims 1 to 6, wherein the compound (C) having a silsesquioxane skeleton has a weight average molecular weight of 1000 or more and 30000 or less. the film. The ceramic green sheet manufacturing process according to any one of claims 1 to 7, wherein the active energy ray-curable compound (A) has three or more (meth)acryloyl groups in one molecule. release film. With respect to the total content of the active energy ray-curable compound (A), the active energy ray-curable compound (B) and the compound (C) having a silsesquioxane skeleton in the release agent composition, The ceramic green sheet manufacturing process according to any one of claims 1 to 8, wherein the content ratio of the active energy ray-curable compound (B) is 0.003 or more and 0.05 or less. release film. 10. The surface free energy of the surface of the release agent layer opposite to the substrate is 15 mJ/m ² or more and 35 mJ/m ² or less, according to any one of claims 1 to 9. release film for ceramic green sheet manufacturing process. The release film for a ceramic green sheet manufacturing process according to any one of claims 1 to 10, wherein the release agent layer has a thickness of 0.05 µm or more and 2.0 µm or less. The ceramic according to any one of claims 1 to 11, wherein the maximum protrusion height (Rp1) on the surface of the release agent layer opposite to the substrate is 5 nm or more and 100 nm or less. Release film for green sheet manufacturing process. The ceramic according to any one of claims 1 to 12, wherein the maximum protrusion height (Rp2) on the surface of the substrate opposite to the release agent layer is 30 nm or more and 500 nm or less. Release film for green sheet manufacturing process. 14. The release film for a ceramic green sheet manufacturing process according to any one of claims 1 to 13, further comprising an antistatic layer between the substrate and the release agent layer.

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